A mechanism that admits continuous free rotation between a fixed platform and a rotating body is described. The mechanism is a serial kinematic chain with several revolute joints. The end of the kinematic chain has free and unlimited rotational motion, equivalent to a standard mechanical pivot, but the travel of each individual joint in the chain is limited to less than +/- 70 degrees. The joints that compose the chain can thus be constructed using compliant flexure hinges. The entire mechanism can be folded from a single flat sheet of material, and is thus well suited for self-assembly by folding, which is an increasingly attractive technique for building micro-scale devices. Potential applications include rotating propellers for micro underwater or fluid-immersed (e.g. within a blood vessel) robots, and high-mobility wheel-legs for crawling vehicles.
The code (*.m files) was last tested with GNU Octave. It should work on Matlab also with minor edits. The folder origami-rotors/patterns/ has templates for paper models in US Letter and A4 paper sizes. The svg files are scalable vector graphics files that can be opened with, for example, Inkscape.
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crcdMakeRibbonMovie.m - Matlab/GNU Octave script creates a short animation of the backbone ribbon
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crcdPlaybackFullChain.m - Matlab/GNU Octave script creates a short animation of the chain of tetrahedral links. At the octave prompt, you will need to call this script from the origami-rotors/code directory.
The animations run nice and quick in Matlab, but quite slowly and with poor lighting in GNU Octave. This may get fixed in the future.
A few videos of the ribbon and chain mechanisms can be found at
- http://youtu.be/gzq5gbF-QC8
- http://youtu.be/ccKN-PoKFPo
- http://youtu.be/AGZfrXsbrTg
- http://youtu.be/dp4zxvpw5og
This project has a Github-hosted website here.
If you would like to reference this work in a publication, please refer to the github url and cite this paper:
"Origami Rotors: Imparting Continuous Rotation to a Moving Platform Using Compliant Flexure Hinges", DETC2013-12753, by Matthew S. Moses, M. Kendal Ackerman, and Gregory S. Chirikjian. In Proceedings of the ASME 2013 International Design Engineering Technical Conferences & Computers and Information in Engineering Conference, IDETC/CIE 2013, August 4-August 7, 2013, Portland, OR, USA.